ve table numbers



i have a speedpro setup on my syclone. what are the numbers representing in the ve table. truck is running a little too rich. if you go up or down numerically what are u doing?also, how do you convert kpa to boost numbers?
The VE number is used by the computer in figuring out what the air flow is through the engine. A higher VE means more air flow, which means more fuel needed to get the same a/f ratio.

If you have the wide band O2, and it comes back saying that the actual a/f ratio is richer than what you specified you wanted there, then it is injecting too much fuel, which means it thinks the air flow is higher than what it really is. So you would reduce your VE in that cell to tell it the air flow is less, which will cut the fuel back some, which will lean it out. Assuming you are running in open loop, closed loop it will do this on its own.

kPa is an absolute pressure measurement, which means that the zero point is a perfect vacuum. psia is also an absolute pressure.

kPa*14.696/101.325 = psia

When most folks talk boost pressure they mean gauge pressure, where the zero point is local atmospheric pressure instead of a perfect vacuum. So you take the absolute pressure and subtract the local air pressure and you get gauge pressure.

psia - atm pressure = psig

Example: How many psig is 250 kPa, if the local air pressure is 27.5 in Hg?

27.5" Hg * 14.696/29.92 = 13.51 psia, this is the local air pressure in psi.

250 kPa * 14.696/101.325 = 36.26 psia, this is the manifold pressure in absolute psi

36.26 - 13.51 = 22.75 psig

So 250 kPa is the same as 22.75 psig boost.

At sea level, or up in the mountains, it might equal more or less psig boost since the local atm pressure is different there.

John Estill